<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="div1">
        你好
    </div>
    <script>
        const mask = document.querySelector('.div1');
       
        mask.style.backgroundColor = 'lightblue'; // 设置背景颜色为浅蓝色
        console.log('mask',mask);
        
    </script>
</body>
</html>